{
ZADATAK: proizvod
JEZIK: PASCAL
}
type TNiz=array[0..100000] of longint;
var
  a,b,c,d,pl:TNiz;
  n,m:longint;
  f,g:text;
  i,j,br,gr:longint;
  z:char;
procedure Sort(l,r:longint);
var
  i,j,x,y:longint;
begin
  i:=l; j:=r; x:=pl[(l+r) div 2];
  repeat
    while pl[i]>x do i:=i+1;
    while x>pl[j] do j:=j-1;
    if i<=j then
    begin
      y:=pl[i]; pl[i]:=pl[j]; pl[j]:=y;
      i:=i+1; j:=j-1;
    end;
  until i>j;
  if l<j then Sort(l,j);
  if i<r then Sort(i,r);
end;
procedure Mnozi(var x:TNiz);
var i,j,k,ind:longint;
begin
  x[0]:=1; x[1]:=0;
  for i:=b[0] downto 1 do
    for j:=a[0] downto 1 do begin
      k:=b[i]*a[j];
      ind:=b[0]+a[0]-i-j+1;
      x[ind]:=x[ind]+(k mod 10);
      k:=k div 10; k:=k+(x[ind] div 10);
      x[ind]:=x[ind] mod 10;
      while k<>0 do begin
        ind:=ind+1;
        x[ind]:=x[ind]+(k mod 10);
        k:=k div 10; k:=k+(x[ind] div 10);
        x[ind]:=x[ind] mod 10;
      end;
      x[0]:=ind;
    end;
end;
function Vece:longint;
var i:longint; q:boolean;
begin
  if c[0]>d[0] then Vece:=1
  else if c[0]<d[0] then Vece:=-1
  else begin
    q:=false;
    i:=c[0];
    while (i>0) and (not q) do begin
      i:=i-1;
      q:=c[i]<>d[i];
    end;
    if not q then Vece:=0
    else if c[i]>d[i] then Vece:=1
    else Vece:=-1;
  end;
end;
begin
  assign(f,'proizvod.in'); reset(f);
  assign(g,'proizvod.out'); rewrite(g);
  readln(f,n,m);
  for i:=1 to n do begin
    read(f,z);
    pl[i]:=ord(z)-48;
  end;
  sort(1,n);
  a[0]:=1; a[1]:=pl[1];
  b[0]:=1; b[1]:=pl[2];
  for i:=3 to n do begin
    fillchar(c,sizeof(c),0);
    fillchar(d,sizeof(d),0);
    a[0]:=a[0]+1;
    a[a[0]]:=pl[i];
    Mnozi(c);
    a[0]:=a[0]-1;
    b[0]:=b[0]+1;
    b[b[0]]:=pl[i];
    Mnozi(d);
    br:=Vece;
    if br=1 then begin
      a[0]:=a[0]+1;
      b[0]:=b[0]-1;
    end
  end;
  fillchar(c,sizeof(c),0);
  Mnozi(c);
  if c[0]>=m then gr:=m
  else begin
    for i:=1 to m-c[0] do write(g,'0');
    gr:=c[0];
  end;
  for i:=gr downto 2 do
    write(g,c[i]);
    writeln(g,c[1]);
  close(f); close(g);
end.